Among conventional machining centers, there is one having a column left/right movably erected on a base, a slider up/down movably provided for the column in a cantilever style, and a slider with a spindle head forward/backward movably provided for the slider in a cantilever style (refer to, for example, Japanese Patent Application Publication No. 2002-200534).
According to this kind of configuration, a drive device for moving the column is arranged on the base and a drive device for up/down moving the slider is arranged on the column. Namely, in the machining center of the above-mentioned configuration, the gravity center position of a movable body such as the slider is greatly distanced from the drive device thereof. There is a problem, therefore, that vibration easily occurs at the time of acceleration or deceleration to move and position the movable body by the drive device.
With that, a technique has been proposed to arrange a drive device on each side of the gravity center position of a movable body and move the movable body by driving the same at the center of gravity thereof with a drive source center being positioned in the vicinity of the center of gravity of the movable body (refer to, for example, Patent Literatures 1, 2, and 3).
Configurations mentioned in the Patent Literatures 1 and 2 each arrange a ball screw serving as a drive device on each side of a movable body, to reciprocate the movable body. A configuration mentioned in the Patent Literature 3 arranges a linear motor as a drive device on each side of a movable body.
The configurations mentioned in the Patent Documents 1 to 3 each arrange the drive device on each side of the gravity center position of the movable body, and therefore, may drive the movable body at the center of gravity thereof.